text: /*
   * RTSP/SDP client
   * Copyright (c) 2002 Fabrice Bellard
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/base64.h"
  #include "libavutil/avstring.h"
  #include "libavutil/intreadwrite.h"
  #include "libavutil/random_seed.h"
  #include "avformat.h"
  
  #include <sys/time.h>
  #if HAVE_SYS_SELECT_H
  #include <sys/select.h>
  #endif
  #include <strings.h>
  #include "internal.h"
  #include "network.h"
  #include "os_support.h"
  #include "http.h"
  #include "rtsp.h"
  
  #include "rtpdec.h"
  #include "rdt.h"
  #include "rtpdec_asf.h"
  
  //#define DEBUG
  //#define DEBUG_RTP_TCP
  
  #if LIBAVFORMAT_VERSION_INT < (53 << 16)
  int rtsp_default_protocols = (1 << RTSP_LOWER_TRANSPORT_UDP);
  #endif
  
  /* Timeout values for socket select, in ms,
   * and read_packet(), in seconds  */
  #define SELECT_TIMEOUT_MS 100
  #define READ_PACKET_TIMEOUT_S 10
  #define MAX_TIMEOUTS READ_PACKET_TIMEOUT_S * 1000 / SELECT_TIMEOUT_MS
  
  static void get_word_until_chars(char *buf, int buf_size,
                                   const char *sep, const char **pp)
  {
      const char *p;
      char *q;
  
      p = *pp;
      p += strspn(p, SPACE_CHARS);
      q = buf;
      while (!strchr(sep, *p) && *p != '\0') {
          if ((q - buf) < buf_size - 1)
              *q++ = *p;
          p++;
      }
      if (buf_size > 0)
          *q = '\0';
      *pp = p;
  }
  
  static void get_word_sep(char *buf, int buf_size, const char *sep,
                           const char **pp)
  {
      if (**pp == '/') (*pp)++;
      get_word_until_chars(buf, buf_size, sep, pp);
  }
  
  static void get_word(char *buf, int buf_size, const char **pp)
  {
      get_word_until_chars(buf, buf_size, SPACE_CHARS, pp);
  }
  
  /* parse the rtpmap description: <codec_name>/<clock_rate>[/<other params>] */
  static int sdp_parse_rtpmap(AVFormatContext *s,
                              AVCodecContext *codec, RTSPStream *rtsp_st,
                              int payload_type, const char *p)
  {
      char buf[256];
      int i;
      AVCodec *c;
      const char *c_name;
  
      /* Loop into AVRtpDynamicPayloadTypes[] and AVRtpPayloadTypes[] and
       * see if we can handle this kind of payload.
       * The space should normally not be there but some Real streams or
       * particular servers ("RealServer Version 6.1.3.970", see issue 1658)
       * have a trailing space. */
      get_word_sep(buf, sizeof(buf), "/ ", &p);
      if (payload_type >= RTP_PT_PRIVATE) {
          RTPDynamicProtocolHandler *handler;
          for (handler = RTPFirstDynamicPayloadHandler;
               handler; handler = handler->next) {
              if (!strcasecmp(buf, handler->enc_name) &&
                  codec->codec_type == handler->codec_type) {
                  codec->codec_id          = handler->codec_id;
                  rtsp_st->dynamic_handler = handler;
                  if (handler->open)
                      rtsp_st->dynamic_protocol_context = handler->open();
                  break;
              }
          }
      } else {
          /* We are in a standard case
           * (from http://www.iana.org/assignments/rtp-parameters). */
          /* search into AVRtpPayloadTypes[] */
          codec->codec_id = ff_rtp_codec_id(buf, codec->codec_type);
      }
  
      c = avcodec_find_decoder(codec->codec_id);
      if (c && c->name)
          c_name = c->name;
      else
          c_name = "(null)";
  
      get_word_sep(buf, sizeof(buf), "/", &p);
      i = atoi(buf);
      switch (codec->codec_type) {
      case AVMEDIA_TYPE_AUDIO:
          av_log(s, AV_LOG_DEBUG, "audio codec set to: %s\n", c_name);
          codec->sample_rate = RTSP_DEFAULT_AUDIO_SAMPLERATE;
          codec->channels = RTSP_DEFAULT_NB_AUDIO_CHANNELS;
          if (i > 0) {
              codec->sample_rate = i;
              get_word_sep(buf, sizeof(buf), "/", &p);
              i = atoi(buf);
              if (i > 0)
                  codec->channels = i;
              // TODO: there is a bug here; if it is a mono stream, and
              // less than 22000Hz, faad upconverts to stereo and twice
              // the frequency.  No problem, but the sample rate is being
              // set here by the sdp line. Patch on its way. (rdm)
          }
          av_log(s, AV_LOG_DEBUG, "audio samplerate set to: %i\n",
                 codec->sample_rate);
          av_log(s, AV_LOG_DEBUG, "audio channels set to: %i\n",
                 codec->channels);
          break;
      case AVMEDIA_TYPE_VIDEO:
          av_log(s, AV_LOG_DEBUG, "video codec set to: %s\n", c_name);
          break;
      default:
          break;
      }
      return 0;
  }
  
  /* parse the attribute line from the fmtp a line of an sdp response. This
   * is broken out as a function because it is used in rtp_h264.c, which is
   * forthcoming. */
  int ff_rtsp_next_attr_and_value(const char **p, char *attr, int attr_size,
                                  char *value, int value_size)
  {
      *p += strspn(*p, SPACE_CHARS);
      if (**p) {
          get_word_sep(attr, attr_size, "=", p);
          if (**p == '=')
              (*p)++;
          get_word_sep(value, value_size, ";", p);
          if (**p == ';')
              (*p)++;
          return 1;
      }
      return 0;
  }
  
  /** Parse a string p in the form of Range:npt=xx-xx, and determine the start
   *  and end time.
   *  Used for seeking in the rtp stream.
   */
  static void rtsp_parse_range_npt(const char *p, int64_t *start, int64_t *end)
  {
      char buf[256];
  
      p += strspn(p, SPACE_CHARS);
      if (!av_stristart(p, "npt=", &p))
          return;
  
      *start = AV_NOPTS_VALUE;
      *end = AV_NOPTS_VALUE;
  
      get_word_sep(buf, sizeof(buf), "-", &p);
      *start = parse_date(buf, 1);
      if (*p == '-') {
          p++;
          get_word_sep(buf, sizeof(buf), "-", &p);
          *end = parse_date(buf, 1);
      }
  //    av_log(NULL, AV_LOG_DEBUG, "Range Start: %lld\n", *start);
  //    av_log(NULL, AV_LOG_DEBUG, "Range End: %lld\n", *end);
  }
  
  typedef struct SDPParseState {
      /* SDP only */
      struct in_addr default_ip;
      int            default_ttl;
      int            skip_media;  ///< set if an unknown m= line occurs
  } SDPParseState;
  
  static void sdp_parse_line(AVFormatContext *s, SDPParseState *s1,
                             int letter, const char *buf)
  {
      RTSPState *rt = s->priv_data;
      char buf1[64], st_type[64];
      const char *p;
      enum AVMediaType codec_type;
      int payload_type, i;
      AVStream *st;
      RTSPStream *rtsp_st;
      struct in_addr sdp_ip;
      int ttl;
  
      dprintf(s, "sdp: %c='%s'\n", letter, buf);
  
      p = buf;
      if (s1->skip_media && letter != 'm')
          return;
      switch (letter) {
      case 'c':
          get_word(buf1, sizeof(buf1), &p);
          if (strcmp(buf1, "IN") != 0)
              return;
          get_word(buf1, sizeof(buf1), &p);
          if (strcmp(buf1, "IP4") != 0)
              return;
          get_word_sep(buf1, sizeof(buf1), "/", &p);
          if (ff_inet_aton(buf1, &sdp_ip) == 0)
              return;
          ttl = 16;
          if (*p == '/') {
              p++;
              get_word_sep(buf1, sizeof(buf1), "/", &p);
              ttl = atoi(buf1);
          }
          if (s->nb_streams == 0) {
              s1->default_ip = sdp_ip;
              s1->default_ttl = ttl;
          } else {
              st = s->streams[s->nb_streams - 1];
              rtsp_st = st->priv_data;
              rtsp_st->sdp_ip = sdp_ip;
              rtsp_st->sdp_ttl = ttl;
          }
          break;
      case 's':
          av_metadata_set2(&s->metadata, "title", p, 0);
          break;
      case 'i':
          if (s->nb_streams == 0) {
              av_metadata_set2(&s->metadata, "comment", p, 0);
              break;
          }
          break;
      case 'm':
          /* new stream */
          s1->skip_media = 0;
          get_word(st_type, sizeof(st_type), &p);
          if (!strcmp(st_type, "audio")) {
              codec_type = AVMEDIA_TYPE_AUDIO;
          } else if (!strcmp(st_type, "video")) {
              codec_type = AVMEDIA_TYPE_VIDEO;
          } else if (!strcmp(st_type, "application")) {
              codec_type = AVMEDIA_TYPE_DATA;
          } else {
              s1->skip_media = 1;
              return;
          }
          rtsp_st = av_mallocz(sizeof(RTSPStream));
          if (!rtsp_st)
              return;
          rtsp_st->stream_index = -1;
          dynarray_add(&rt->rtsp_streams, &rt->nb_rtsp_streams, rtsp_st);
  
          rtsp_st->sdp_ip = s1->default_ip;
          rtsp_st->sdp_ttl = s1->default_ttl;
  
          get_word(buf1, sizeof(buf1), &p); /* port */
          rtsp_st->sdp_port = atoi(buf1);
  
          get_word(buf1, sizeof(buf1), &p); /* protocol (ignored) */
  
          /* XXX: handle list of formats */
          get_word(buf1, sizeof(buf1), &p); /* format list */
          rtsp_st->sdp_payload_type = atoi(buf1);
  
          if (!strcmp(ff_rtp_enc_name(rtsp_st->sdp_payload_type), "MP2T")) {
              /* no corresponding stream */
          } else {
              st = av_new_stream(s, 0);
              if (!st)
                  return;
              st->priv_data = rtsp_st;
              rtsp_st->stream_index = st->index;
              st->codec->codec_type = codec_type;
              if (rtsp_st->sdp_payload_type < RTP_PT_PRIVATE) {
                  /* if standard payload type, we can find the codec right now */
                  ff_rtp_get_codec_info(st->codec, rtsp_st->sdp_payload_type);
              }
          }
          /* put a default control url */
          av_strlcpy(rtsp_st->control_url, rt->control_uri,
                     sizeof(rtsp_st->control_url));
          break;
      case 'a':
          if (av_strstart(p, "control:", &p)) {
              if (s->nb_streams == 0) {
                  if (!strncmp(p, "rtsp://", 7))
                      av_strlcpy(rt->control_uri, p,
                                 sizeof(rt->control_uri));
              } else {
              char proto[32];
              /* get the control url */
              st = s->streams[s->nb_streams - 1];
              rtsp_st = st->priv_data;
  
              /* XXX: may need to add full url resolution */
              av_url_split(proto, sizeof(proto), NULL, 0, NULL, 0,
                           NULL, NULL, 0, p);
              if (proto[0] == '\0') {
                  /* relative control URL */
                  if (rtsp_st->control_url[strlen(rtsp_st->control_url)-1]!='/')
                  av_strlcat(rtsp_st->control_url, "/",
                             sizeof(rtsp_st->control_url));
                  av_strlcat(rtsp_st->control_url, p,
                             sizeof(rtsp_st->control_url));
              } else
                  av_strlcpy(rtsp_st->control_url, p,
                             sizeof(rtsp_st->control_url));
              }
          } else if (av_strstart(p, "rtpmap:", &p) && s->nb_streams > 0) {
              /* NOTE: rtpmap is only supported AFTER the 'm=' tag */
              get_word(buf1, sizeof(buf1), &p);
              payload_type = atoi(buf1);
              st = s->streams[s->nb_streams - 1];
              rtsp_st = st->priv_data;
              sdp_parse_rtpmap(s, st->codec, rtsp_st, payload_type, p);
          } else if (av_strstart(p, "fmtp:", &p) ||
                     av_strstart(p, "framesize:", &p)) {
              /* NOTE: fmtp is only supported AFTER the 'a=rtpmap:xxx' tag */
              // let dynamic protocol handlers have a stab at the line.
              get_word(buf1, sizeof(buf1), &p);
              payload_type = atoi(buf1);
              for (i = 0; i < s->nb_streams; i++) {
                  st      = s->streams[i];
                  rtsp_st = st->priv_data;
                  if (rtsp_st->sdp_payload_type == payload_type &&
                      rtsp_st->dynamic_handler &&
                      rtsp_st->dynamic_handler->parse_sdp_a_line)
                      rtsp_st->dynamic_handler->parse_sdp_a_line(s, i,
                          rtsp_st->dynamic_protocol_context, buf);
              }
          } else if (av_strstart(p, "range:", &p)) {
              int64_t start, end;
  
              // this is so that seeking on a streamed file can work.
              rtsp_parse_range_npt(p, &start, &end);
              s->start_time = start;
              /* AV_NOPTS_VALUE means live broadcast (and can't seek) */
              s->duration   = (end == AV_NOPTS_VALUE) ?
                              AV_NOPTS_VALUE : end - start;
          } else if (av_strstart(p, "IsRealDataType:integer;",&p)) {
              if (atoi(p) == 1)
                  rt->transport = RTSP_TRANSPORT_RDT;
          } else {
              if (rt->server_type == RTSP_SERVER_WMS)
                  ff_wms_parse_sdp_a_line(s, p);
              if (s->nb_streams > 0) {
                  if (rt->server_type == RTSP_SERVER_REAL)
                      ff_real_parse_sdp_a_line(s, s->nb_streams - 1, p);
  
                  rtsp_st = s->streams[s->nb_streams - 1]->priv_data;
                  if (rtsp_st->dynamic_handler &&
                      rtsp_st->dynamic_handler->parse_sdp_a_line)
                      rtsp_st->dynamic_handler->parse_sdp_a_line(s,
                          s->nb_streams - 1,
                          rtsp_st->dynamic_protocol_context, buf);
              }
          }
          break;
      }
  }
  
  static int sdp_parse(AVFormatContext *s, const char *content)
  {
      const char *p;
      int letter;
      /* Some SDP lines, particularly for Realmedia or ASF RTSP streams,
       * contain long SDP lines containing complete ASF Headers (several
       * kB) or arrays of MDPR (RM stream descriptor) headers plus
       * "rulebooks" describing their properties. Therefore, the SDP line
       * buffer is large.
       *
       * The Vorbis FMTP line can be up to 16KB - see xiph_parse_sdp_line
       * in rtpdec_xiph.c. */
      char buf[16384], *q;
      SDPParseState sdp_parse_state, *s1 = &sdp_parse_state;
  
      memset(s1, 0, sizeof(SDPParseState));
      p = content;
      for (;;) {
          p += strspn(p, SPACE_CHARS);
          letter = *p;
          if (letter == '\0')
              break;
          p++;
          if (*p != '=')
              goto next_line;
          p++;
          /* get the content */
          q = buf;
          while (*p != '\n' && *p != '\r' && *p != '\0') {
              if ((q - buf) < sizeof(buf) - 1)
                  *q++ = *p;
              p++;
          }
          *q = '\0';
          sdp_parse_line(s, s1, letter, buf);
      next_line:
          while (*p != '\n' && *p != '\0')
              p++;
          if (*p == '\n')
              p++;
      }
      return 0;
  }
  
  /* close and free RTSP streams */
  void ff_rtsp_close_streams(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
      int i;
      RTSPStream *rtsp_st;
  
      for (i = 0; i < rt->nb_rtsp_streams; i++) {
          rtsp_st = rt->rtsp_streams[i];
          if (rtsp_st) {
              if (rtsp_st->transport_priv) {
                  if (s->oformat) {
                      AVFormatContext *rtpctx = rtsp_st->transport_priv;
                      av_write_trailer(rtpctx);
                      if (rt->lower_transport == RTSP_LOWER_TRANSPORT_TCP) {
                          uint8_t *ptr;
                          url_close_dyn_buf(rtpctx->pb, &ptr);
                          av_free(ptr);
                      } else {
                          url_fclose(rtpctx->pb);
                      }
                      av_metadata_free(&rtpctx->streams[0]->metadata);
                      av_metadata_free(&rtpctx->metadata);
                      av_free(rtpctx->streams[0]);
                      av_free(rtpctx);
                  } else if (rt->transport == RTSP_TRANSPORT_RDT)
                      ff_rdt_parse_close(rtsp_st->transport_priv);
                  else
                      rtp_parse_close(rtsp_st->transport_priv);
              }
              if (rtsp_st->rtp_handle)
                  url_close(rtsp_st->rtp_handle);
              if (rtsp_st->dynamic_handler && rtsp_st->dynamic_protocol_context)
                  rtsp_st->dynamic_handler->close(
                      rtsp_st->dynamic_protocol_context);
          }
      }
      av_free(rt->rtsp_streams);
      if (rt->asf_ctx) {
          av_close_input_stream (rt->asf_ctx);
          rt->asf_ctx = NULL;
      }
  }
  
  static void *rtsp_rtp_mux_open(AVFormatContext *s, AVStream *st,
                                 URLContext *handle)
  {
      RTSPState *rt = s->priv_data;
      AVFormatContext *rtpctx;
      int ret;
      AVOutputFormat *rtp_format = av_guess_format("rtp", NULL, NULL);
  
      if (!rtp_format)
          return NULL;
  
      /* Allocate an AVFormatContext for each output stream */
      rtpctx = avformat_alloc_context();
      if (!rtpctx)
          return NULL;
  
      rtpctx->oformat = rtp_format;
      if (!av_new_stream(rtpctx, 0)) {
          av_free(rtpctx);
          return NULL;
      }
      /* Copy the max delay setting; the rtp muxer reads this. */
      rtpctx->max_delay = s->max_delay;
      /* Copy other stream parameters. */
      rtpctx->streams[0]->sample_aspect_ratio = st->sample_aspect_ratio;
  
      /* Set the synchronized start time. */
      rtpctx->start_time_realtime = rt->start_time;
  
      /* Remove the local codec, link to the original codec
       * context instead, to give the rtp muxer access to
       * codec parameters. */
      av_free(rtpctx->streams[0]->codec);
      rtpctx->streams[0]->codec = st->codec;
  
      if (handle) {
          url_fdopen(&rtpctx->pb, handle);
      } else
          url_open_dyn_packet_buf(&rtpctx->pb, RTSP_TCP_MAX_PACKET_SIZE);
      ret = av_write_header(rtpctx);
  
      if (ret) {
          if (handle) {
              url_fclose(rtpctx->pb);
          } else {
              uint8_t *ptr;
              url_close_dyn_buf(rtpctx->pb, &ptr);
              av_free(ptr);
          }
          av_free(rtpctx->streams[0]);
          av_free(rtpctx);
          return NULL;
      }
  
      /* Copy the RTP AVStream timebase back to the original AVStream */
      st->time_base = rtpctx->streams[0]->time_base;
      return rtpctx;
  }
  
  static int rtsp_open_transport_ctx(AVFormatContext *s, RTSPStream *rtsp_st)
  {
      RTSPState *rt = s->priv_data;
      AVStream *st = NULL;
  
      /* open the RTP context */
      if (rtsp_st->stream_index >= 0)
          st = s->streams[rtsp_st->stream_index];
      if (!st)
          s->ctx_flags |= AVFMTCTX_NOHEADER;
  
      if (s->oformat) {
          rtsp_st->transport_priv = rtsp_rtp_mux_open(s, st, rtsp_st->rtp_handle);
          /* Ownership of rtp_handle is passed to the rtp mux context */
          rtsp_st->rtp_handle = NULL;
      } else if (rt->transport == RTSP_TRANSPORT_RDT)
          rtsp_st->transport_priv = ff_rdt_parse_open(s, st->index,
                                              rtsp_st->dynamic_protocol_context,
                                              rtsp_st->dynamic_handler);
      else
          rtsp_st->transport_priv = rtp_parse_open(s, st, rtsp_st->rtp_handle,
                                           rtsp_st->sdp_payload_type);
  
      if (!rtsp_st->transport_priv) {
           return AVERROR(ENOMEM);
      } else if (rt->transport != RTSP_TRANSPORT_RDT) {
          if (rtsp_st->dynamic_handler) {
              rtp_parse_set_dynamic_protocol(rtsp_st->transport_priv,
                                             rtsp_st->dynamic_protocol_context,
                                             rtsp_st->dynamic_handler);
          }
      }
  
      return 0;
  }
  
  #if CONFIG_RTSP_DEMUXER || CONFIG_RTSP_MUXER
  static int rtsp_probe(AVProbeData *p)
  {
      if (av_strstart(p->filename, "rtsp:", NULL))
          return AVPROBE_SCORE_MAX;
      return 0;
  }
  
  static void rtsp_parse_range(int *min_ptr, int *max_ptr, const char **pp)
  {
      const char *p;
      int v;
  
      p = *pp;
      p += strspn(p, SPACE_CHARS);
      v = strtol(p, (char **)&p, 10);
      if (*p == '-') {
          p++;
          *min_ptr = v;
          v = strtol(p, (char **)&p, 10);
          *max_ptr = v;
      } else {
          *min_ptr = v;
          *max_ptr = v;
      }
      *pp = p;
  }
  
  /* XXX: only one transport specification is parsed */
  static void rtsp_parse_transport(RTSPMessageHeader *reply, const char *p)
  {
      char transport_protocol[16];
      char profile[16];
      char lower_transport[16];
      char parameter[16];
      RTSPTransportField *th;
      char buf[256];
  
      reply->nb_transports = 0;
  
      for (;;) {
          p += strspn(p, SPACE_CHARS);
          if (*p == '\0')
              break;
  
          th = &reply->transports[reply->nb_transports];
  
          get_word_sep(transport_protocol, sizeof(transport_protocol),
                       "/", &p);
          if (!strcasecmp (transport_protocol, "rtp")) {
              get_word_sep(profile, sizeof(profile), "/;,", &p);
              lower_transport[0] = '\0';
              /* rtp/avp/<protocol> */
              if (*p == '/') {
                  get_word_sep(lower_transport, sizeof(lower_transport),
                               ";,", &p);
              }
              th->transport = RTSP_TRANSPORT_RTP;
          } else if (!strcasecmp (transport_protocol, "x-pn-tng") ||
                     !strcasecmp (transport_protocol, "x-real-rdt")) {
              /* x-pn-tng/<protocol> */
              get_word_sep(lower_transport, sizeof(lower_transport), "/;,", &p);
              profile[0] = '\0';
              th->transport = RTSP_TRANSPORT_RDT;
          }
          if (!strcasecmp(lower_transport, "TCP"))
              th->lower_transport = RTSP_LOWER_TRANSPORT_TCP;
          else
              th->lower_transport = RTSP_LOWER_TRANSPORT_UDP;
  
          if (*p == ';')
              p++;
          /* get each parameter */
          while (*p != '\0' && *p != ',') {
              get_word_sep(parameter, sizeof(parameter), "=;,", &p);
              if (!strcmp(parameter, "port")) {
                  if (*p == '=') {
                      p++;
                      rtsp_parse_range(&th->port_min, &th->port_max, &p);
                  }
              } else if (!strcmp(parameter, "client_port")) {
                  if (*p == '=') {
                      p++;
                      rtsp_parse_range(&th->client_port_min,
                                       &th->client_port_max, &p);
                  }
              } else if (!strcmp(parameter, "server_port")) {
                  if (*p == '=') {
                      p++;
                      rtsp_parse_range(&th->server_port_min,
                                       &th->server_port_max, &p);
                  }
              } else if (!strcmp(parameter, "interleaved")) {
                  if (*p == '=') {
                      p++;
                      rtsp_parse_range(&th->interleaved_min,
                                       &th->interleaved_max, &p);
                  }
              } else if (!strcmp(parameter, "multicast")) {
                  if (th->lower_transport == RTSP_LOWER_TRANSPORT_UDP)
                      th->lower_transport = RTSP_LOWER_TRANSPORT_UDP_MULTICAST;
              } else if (!strcmp(parameter, "ttl")) {
                  if (*p == '=') {
                      p++;
                      th->ttl = strtol(p, (char **)&p, 10);
                  }
              } else if (!strcmp(parameter, "destination")) {
                  struct in_addr ipaddr;
  
                  if (*p == '=') {
                      p++;
                      get_word_sep(buf, sizeof(buf), ";,", &p);
                      if (ff_inet_aton(buf, &ipaddr))
                          th->destination = ntohl(ipaddr.s_addr);
                  }
              }
              while (*p != ';' && *p != '\0' && *p != ',')
                  p++;
              if (*p == ';')
                  p++;
          }
          if (*p == ',')
              p++;
  
          reply->nb_transports++;
      }
  }
  
  void ff_rtsp_parse_line(RTSPMessageHeader *reply, const char *buf,
                          HTTPAuthState *auth_state)
  {
      const char *p;
  
      /* NOTE: we do case independent match for broken servers */
      p = buf;
      if (av_stristart(p, "Session:", &p)) {
          int t;
          get_word_sep(reply->session_id, sizeof(reply->session_id), ";", &p);
          if (av_stristart(p, ";timeout=", &p) &&
              (t = strtol(p, NULL, 10)) > 0) {
              reply->timeout = t;
          }
      } else if (av_stristart(p, "Content-Length:", &p)) {
          reply->content_length = strtol(p, NULL, 10);
      } else if (av_stristart(p, "Transport:", &p)) {
          rtsp_parse_transport(reply, p);
      } else if (av_stristart(p, "CSeq:", &p)) {
          reply->seq = strtol(p, NULL, 10);
      } else if (av_stristart(p, "Range:", &p)) {
          rtsp_parse_range_npt(p, &reply->range_start, &reply->range_end);
      } else if (av_stristart(p, "RealChallenge1:", &p)) {
          p += strspn(p, SPACE_CHARS);
          av_strlcpy(reply->real_challenge, p, sizeof(reply->real_challenge));
      } else if (av_stristart(p, "Server:", &p)) {
          p += strspn(p, SPACE_CHARS);
          av_strlcpy(reply->server, p, sizeof(reply->server));
      } else if (av_stristart(p, "Notice:", &p) ||
                 av_stristart(p, "X-Notice:", &p)) {
          reply->notice = strtol(p, NULL, 10);
      } else if (av_stristart(p, "Location:", &p)) {
          p += strspn(p, SPACE_CHARS);
          av_strlcpy(reply->location, p , sizeof(reply->location));
      } else if (av_stristart(p, "WWW-Authenticate:", &p) && auth_state) {
          p += strspn(p, SPACE_CHARS);
          ff_http_auth_handle_header(auth_state, "WWW-Authenticate", p);
      } else if (av_stristart(p, "Authentication-Info:", &p) && auth_state) {
          p += strspn(p, SPACE_CHARS);
          ff_http_auth_handle_header(auth_state, "Authentication-Info", p);
      }
  }
  
  /* skip a RTP/TCP interleaved packet */
  void ff_rtsp_skip_packet(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
      int ret, len, len1;
      uint8_t buf[1024];
  
      ret = url_read_complete(rt->rtsp_hd, buf, 3);
      if (ret != 3)
          return;
      len = AV_RB16(buf + 1);
  
      dprintf(s, "skipping RTP packet len=%d\n", len);
  
      /* skip payload */
      while (len > 0) {
          len1 = len;
          if (len1 > sizeof(buf))
              len1 = sizeof(buf);
          ret = url_read_complete(rt->rtsp_hd, buf, len1);
          if (ret != len1)
              return;
          len -= len1;
      }
  }
  
  int ff_rtsp_read_reply(AVFormatContext *s, RTSPMessageHeader *reply,
                         unsigned char **content_ptr,
                         int return_on_interleaved_data)
  {
      RTSPState *rt = s->priv_data;
      char buf[4096], buf1[1024], *q;
      unsigned char ch;
      const char *p;
      int ret, content_length, line_count = 0;
      unsigned char *content = NULL;
  
      memset(reply, 0, sizeof(*reply));
  
      /* parse reply (XXX: use buffers) */
      rt->last_reply[0] = '\0';
      for (;;) {
          q = buf;
          for (;;) {
              ret = url_read_complete(rt->rtsp_hd, &ch, 1);
  #ifdef DEBUG_RTP_TCP
              dprintf(s, "ret=%d c=%02x [%c]\n", ret, ch, ch);
  #endif
              if (ret != 1)
                  return -1;
              if (ch == '\n')
                  break;
              if (ch == '$') {
                  /* XXX: only parse it if first char on line ? */
                  if (return_on_interleaved_data) {
                      return 1;
                  } else
                      ff_rtsp_skip_packet(s);
              } else if (ch != '\r') {
                  if ((q - buf) < sizeof(buf) - 1)
                      *q++ = ch;
              }
          }
          *q = '\0';
  
          dprintf(s, "line='%s'\n", buf);
  
          /* test if last line */
          if (buf[0] == '\0')
              break;
          p = buf;
          if (line_count == 0) {
              /* get reply code */
              get_word(buf1, sizeof(buf1), &p);
              get_word(buf1, sizeof(buf1), &p);
              reply->status_code = atoi(buf1);
          } else {
              ff_rtsp_parse_line(reply, p, &rt->auth_state);
              av_strlcat(rt->last_reply, p,    sizeof(rt->last_reply));
              av_strlcat(rt->last_reply, "\n", sizeof(rt->last_reply));
          }
          line_count++;
      }
  
      if (rt->session_id[0] == '\0' && reply->session_id[0] != '\0')
          av_strlcpy(rt->session_id, reply->session_id, sizeof(rt->session_id));
  
      content_length = reply->content_length;
      if (content_length > 0) {
          /* leave some room for a trailing '\0' (useful for simple parsing) */
          content = av_malloc(content_length + 1);
          (void)url_read_complete(rt->rtsp_hd, content, content_length);
          content[content_length] = '\0';
      }
      if (content_ptr)
          *content_ptr = content;
      else
          av_free(content);
  
      if (rt->seq != reply->seq) {
          av_log(s, AV_LOG_WARNING, "CSeq %d expected, %d received.\n",
              rt->seq, reply->seq);
      }
  
      /* EOS */
      if (reply->notice == 2101 /* End-of-Stream Reached */      ||
          reply->notice == 2104 /* Start-of-Stream Reached */    ||
          reply->notice == 2306 /* Continuous Feed Terminated */) {
          rt->state = RTSP_STATE_IDLE;
      } else if (reply->notice >= 4400 && reply->notice < 5500) {
          return AVERROR(EIO); /* data or server error */
      } else if (reply->notice == 2401 /* Ticket Expired */ ||
               (reply->notice >= 5500 && reply->notice < 5600) /* end of term */ )
          return AVERROR(EPERM);
  
      return 0;
  }
  
  int ff_rtsp_send_cmd_with_content_async(AVFormatContext *s,
                                          const char *method, const char *url,
                                          const char *headers,
                                          const unsigned char *send_content,
                                          int send_content_length)
  {
      RTSPState *rt = s->priv_data;
      char buf[4096], *out_buf;
      char base64buf[AV_BASE64_SIZE(sizeof(buf))];
  
      /* Add in RTSP headers */
      out_buf = buf;
      rt->seq++;
      snprintf(buf, sizeof(buf), "%s %s RTSP/1.0\r\n", method, url);
      if (headers)
          av_strlcat(buf, headers, sizeof(buf));
      av_strlcatf(buf, sizeof(buf), "CSeq: %d\r\n", rt->seq);
      if (rt->session_id[0] != '\0' && (!headers ||
          !strstr(headers, "\nIf-Match:"))) {
          av_strlcatf(buf, sizeof(buf), "Session: %s\r\n", rt->session_id);
      }
      if (rt->auth[0]) {
          char *str = ff_http_auth_create_response(&rt->auth_state,
                                                   rt->auth, url, method);
          if (str)
              av_strlcat(buf, str, sizeof(buf));
          av_free(str);
      }
      if (send_content_length > 0 && send_content)
          av_strlcatf(buf, sizeof(buf), "Content-Length: %d\r\n", send_content_length);
      av_strlcat(buf, "\r\n", sizeof(buf));
  
      /* base64 encode rtsp if tunneling */
      if (rt->control_transport == RTSP_MODE_TUNNEL) {
          av_base64_encode(base64buf, sizeof(base64buf), buf, strlen(buf));
          out_buf = base64buf;
      }
  
      dprintf(s, "Sending:\n%s--\n", buf);
  
      url_write(rt->rtsp_hd_out, out_buf, strlen(out_buf));
      if (send_content_length > 0 && send_content) {
          if (rt->control_transport == RTSP_MODE_TUNNEL) {
              av_log(s, AV_LOG_ERROR, "tunneling of RTSP requests "
                                      "with content data not supported\n");
              return AVERROR_PATCHWELCOME;
          }
          url_write(rt->rtsp_hd_out, send_content, send_content_length);
      }
      rt->last_cmd_time = av_gettime();
  
      return 0;
  }
  
  int ff_rtsp_send_cmd_async(AVFormatContext *s, const char *method,
                             const char *url, const char *headers)
  {
      return ff_rtsp_send_cmd_with_content_async(s, method, url, headers, NULL, 0);
  }
  
  int ff_rtsp_send_cmd(AVFormatContext *s, const char *method, const char *url,
                       const char *headers, RTSPMessageHeader *reply,
                       unsigned char **content_ptr)
  {
      return ff_rtsp_send_cmd_with_content(s, method, url, headers, reply,
                                           content_ptr, NULL, 0);
  }
  
  int ff_rtsp_send_cmd_with_content(AVFormatContext *s,
                                    const char *method, const char *url,
                                    const char *header,
                                    RTSPMessageHeader *reply,
                                    unsigned char **content_ptr,
                                    const unsigned char *send_content,
                                    int send_content_length)
  {
      RTSPState *rt = s->priv_data;
      HTTPAuthType cur_auth_type;
      int ret;
  
  retry:
      cur_auth_type = rt->auth_state.auth_type;
      if ((ret = ff_rtsp_send_cmd_with_content_async(s, method, url, header,
                                                     send_content,
                                                     send_content_length)))
          return ret;
  
      if ((ret = ff_rtsp_read_reply(s, reply, content_ptr, 0) ) < 0)
          return ret;
  
      if (reply->status_code == 401 && cur_auth_type == HTTP_AUTH_NONE &&
          rt->auth_state.auth_type != HTTP_AUTH_NONE)
          goto retry;
  
      if (reply->status_code > 400){
          av_log(s, AV_LOG_ERROR, "method %s failed, %d\n",
                 method,
                 reply->status_code);
          av_log(s, AV_LOG_DEBUG, "%s\n", rt->last_reply);
      }
  
      return 0;
  }
  
  /**
   * @return 0 on success, <0 on error, 1 if protocol is unavailable.
   */
  static int make_setup_request(AVFormatContext *s, const char *host, int port,
                                int lower_transport, const char *real_challenge)
  {
      RTSPState *rt = s->priv_data;
      int rtx, j, i, err, interleave = 0;
      RTSPStream *rtsp_st;
      RTSPMessageHeader reply1, *reply = &reply1;
      char cmd[2048];
      const char *trans_pref;
  
      if (rt->transport == RTSP_TRANSPORT_RDT)
          trans_pref = "x-pn-tng";
      else
          trans_pref = "RTP/AVP";
  
      /* default timeout: 1 minute */
      rt->timeout = 60;
  
      /* for each stream, make the setup request */
      /* XXX: we assume the same server is used for the control of each
       * RTSP stream */
  
      for (j = RTSP_RTP_PORT_MIN, i = 0; i < rt->nb_rtsp_streams; ++i) {
          char transport[2048];
  
          /**
           * WMS serves all UDP data over a single connection, the RTX, which
           * isn't necessarily the first in the SDP but has to be the first
           * to be set up, else the second/third SETUP will fail with a 461.
           */
          if (lower_transport == RTSP_LOWER_TRANSPORT_UDP &&
               rt->server_type == RTSP_SERVER_WMS) {
              if (i == 0) {
                  /* rtx first */
                  for (rtx = 0; rtx < rt->nb_rtsp_streams; rtx++) {
                      int len = strlen(rt->rtsp_streams[rtx]->control_url);
                      if (len >= 4 &&
                          !strcmp(rt->rtsp_streams[rtx]->control_url + len - 4,
                                  "/rtx"))
                          break;
                  }
                  if (rtx == rt->nb_rtsp_streams)
                      return -1; /* no RTX found */
                  rtsp_st = rt->rtsp_streams[rtx];
              } else
                  rtsp_st = rt->rtsp_streams[i > rtx ? i : i - 1];
          } else
              rtsp_st = rt->rtsp_streams[i];
  
          /* RTP/UDP */
          if (lower_transport == RTSP_LOWER_TRANSPORT_UDP) {
              char buf[256];
  
              if (rt->server_type == RTSP_SERVER_WMS && i > 1) {
                  port = reply->transports[0].client_port_min;
                  goto have_port;
              }
  
              /* first try in specified port range */
              if (RTSP_RTP_PORT_MIN != 0) {
                  while (j <= RTSP_RTP_PORT_MAX) {
                      ff_url_join(buf, sizeof(buf), "rtp", NULL, host, -1,
                                  "?localport=%d", j);
                      /* we will use two ports per rtp stream (rtp and rtcp) */
                      j += 2;
                      if (url_open(&rtsp_st->rtp_handle, buf, URL_RDWR) == 0)
                          goto rtp_opened;
                  }
              }
  
  #if 0
              /* then try on any port */
              if (url_open(&rtsp_st->rtp_handle, "rtp://", URL_RDONLY) < 0) {
                  err = AVERROR_INVALIDDATA;
                  goto fail;
              }
  #endif
  
          rtp_opened:
              port = rtp_get_local_port(rtsp_st->rtp_handle);
          have_port:
              snprintf(transport, sizeof(transport) - 1,
                       "%s/UDP;", trans_pref);
              if (rt->server_type != RTSP_SERVER_REAL)
                  av_strlcat(transport, "unicast;", sizeof(transport));
              av_strlcatf(transport, sizeof(transport),
                       "client_port=%d", port);
              if (rt->transport == RTSP_TRANSPORT_RTP &&
                  !(rt->server_type == RTSP_SERVER_WMS && i > 0))
                  av_strlcatf(transport, sizeof(transport), "-%d", port + 1);
          }
  
          /* RTP/TCP */
          else if (lower_transport == RTSP_LOWER_TRANSPORT_TCP) {
              /** For WMS streams, the application streams are only used for
               * UDP. When trying to set it up for TCP streams, the server
               * will return an error. Therefore, we skip those streams. */
              if (rt->server_type == RTSP_SERVER_WMS &&
                  s->streams[rtsp_st->stream_index]->codec->codec_type ==
                      AVMEDIA_TYPE_DATA)
                  continue;
              snprintf(transport, sizeof(transport) - 1,
                       "%s/TCP;", trans_pref);
              if (rt->server_type == RTSP_SERVER_WMS)
                  av_strlcat(transport, "unicast;", sizeof(transport));
              av_strlcatf(transport, sizeof(transport),
                          "interleaved=%d-%d",
                          interleave, interleave + 1);
              interleave += 2;
          }
  
          else if (lower_transport == RTSP_LOWER_TRANSPORT_UDP_MULTICAST) {
              snprintf(transport, sizeof(transport) - 1,
                       "%s/UDP;multicast", trans_pref);
          }
          if (s->oformat) {
              av_strlcat(transport, ";mode=receive", sizeof(transport));
          } else if (rt->server_type == RTSP_SERVER_REAL ||
                     rt->server_type == RTSP_SERVER_WMS)
              av_strlcat(transport, ";mode=play", sizeof(transport));
          snprintf(cmd, sizeof(cmd),
                   "Transport: %s\r\n",
                   transport);
          if (i == 0 && rt->server_type == RTSP_SERVER_REAL) {
              char real_res[41], real_csum[9];
              ff_rdt_calc_response_and_checksum(real_res, real_csum,
                                                real_challenge);
              av_strlcatf(cmd, sizeof(cmd),
                          "If-Match: %s\r\n"
                          "RealChallenge2: %s, sd=%s\r\n",
                          rt->session_id, real_res, real_csum);
          }
          ff_rtsp_send_cmd(s, "SETUP", rtsp_st->control_url, cmd, reply, NULL);
          if (reply->status_code == 461 /* Unsupported protocol */ && i == 0) {
              err = 1;
              goto fail;
          } else if (reply->status_code != RTSP_STATUS_OK ||
                     reply->nb_transports != 1) {
              err = AVERROR_INVALIDDATA;
              goto fail;
          }
  
          /* XXX: same protocol for all streams is required */
          if (i > 0) {
              if (reply->transports[0].lower_transport != rt->lower_transport ||
                  reply->transports[0].transport != rt->transport) {
                  err = AVERROR_INVALIDDATA;
                  goto fail;
              }
          } else {
              rt->lower_transport = reply->transports[0].lower_transport;
              rt->transport = reply->transports[0].transport;
          }
  
          /* close RTP connection if not choosen */
          if (reply->transports[0].lower_transport != RTSP_LOWER_TRANSPORT_UDP &&
              (lower_transport == RTSP_LOWER_TRANSPORT_UDP)) {
              url_close(rtsp_st->rtp_handle);
              rtsp_st->rtp_handle = NULL;
          }
  
          switch(reply->transports[0].lower_transport) {
          case RTSP_LOWER_TRANSPORT_TCP:
              rtsp_st->interleaved_min = reply->transports[0].interleaved_min;
              rtsp_st->interleaved_max = reply->transports[0].interleaved_max;
              break;
  
          case RTSP_LOWER_TRANSPORT_UDP: {
              char url[1024];
  
              /* XXX: also use address if specified */
              ff_url_join(url, sizeof(url), "rtp", NULL, host,
                          reply->transports[0].server_port_min, NULL);
              if (!(rt->server_type == RTSP_SERVER_WMS && i > 1) &&
                  rtp_set_remote_url(rtsp_st->rtp_handle, url) < 0) {
                  err = AVERROR_INVALIDDATA;
                  goto fail;
              }
              /* Try to initialize the connection state in a
               * potential NAT router by sending dummy packets.
               * RTP/RTCP dummy packets are used for RDT, too.
               */
              if (!(rt->server_type == RTSP_SERVER_WMS && i > 1) && s->iformat)
                  rtp_send_punch_packets(rtsp_st->rtp_handle);
              break;
          }
          case RTSP_LOWER_TRANSPORT_UDP_MULTICAST: {
              char url[1024];
              struct in_addr in;
              int port, ttl;
  
              if (reply->transports[0].destination) {
                  in.s_addr = htonl(reply->transports[0].destination);
                  port      = reply->transports[0].port_min;
                  ttl       = reply->transports[0].ttl;
              } else {
                  in        = rtsp_st->sdp_ip;
                  port      = rtsp_st->sdp_port;
                  ttl       = rtsp_st->sdp_ttl;
              }
              ff_url_join(url, sizeof(url), "rtp", NULL, inet_ntoa(in),
                          port, "?ttl=%d", ttl);
              if (url_open(&rtsp_st->rtp_handle, url, URL_RDWR) < 0) {
                  err = AVERROR_INVALIDDATA;
                  goto fail;
              }
              break;
          }
          }
  
          if ((err = rtsp_open_transport_ctx(s, rtsp_st)))
              goto fail;
      }
  
      if (reply->timeout > 0)
          rt->timeout = reply->timeout;
  
      if (rt->server_type == RTSP_SERVER_REAL)
          rt->need_subscription = 1;
  
      return 0;
  
  fail:
      for (i = 0; i < rt->nb_rtsp_streams; i++) {
          if (rt->rtsp_streams[i]->rtp_handle) {
              url_close(rt->rtsp_streams[i]->rtp_handle);
              rt->rtsp_streams[i]->rtp_handle = NULL;
          }
      }
      return err;
  }
  
  static int rtsp_read_play(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
      RTSPMessageHeader reply1, *reply = &reply1;
      int i;
      char cmd[1024];
  
      av_log(s, AV_LOG_DEBUG, "hello state=%d\n", rt->state);
  
      if (!(rt->server_type == RTSP_SERVER_REAL && rt->need_subscription)) {
          if (rt->state == RTSP_STATE_PAUSED) {
              cmd[0] = 0;
          } else {
              snprintf(cmd, sizeof(cmd),
                       "Range: npt=%0.3f-\r\n",
                       (double)rt->seek_timestamp / AV_TIME_BASE);
          }
          ff_rtsp_send_cmd(s, "PLAY", rt->control_uri, cmd, reply, NULL);
          if (reply->status_code != RTSP_STATUS_OK) {
              return -1;
          }
          if (reply->range_start != AV_NOPTS_VALUE &&
              rt->transport == RTSP_TRANSPORT_RTP) {
              for (i = 0; i < rt->nb_rtsp_streams; i++) {
                  RTSPStream *rtsp_st = rt->rtsp_streams[i];
                  RTPDemuxContext *rtpctx = rtsp_st->transport_priv;
                  AVStream *st = NULL;
                  if (!rtpctx)
                      continue;
                  if (rtsp_st->stream_index >= 0)
                      st = s->streams[rtsp_st->stream_index];
                  rtpctx->last_rtcp_ntp_time  = AV_NOPTS_VALUE;
                  rtpctx->first_rtcp_ntp_time = AV_NOPTS_VALUE;
                  if (st)
                      rtpctx->range_start_offset = av_rescale_q(reply->range_start,
                                                                AV_TIME_BASE_Q,
                                                                st->time_base);
              }
          }
      }
      rt->state = RTSP_STATE_STREAMING;
      return 0;
  }
  
  static int rtsp_setup_input_streams(AVFormatContext *s, RTSPMessageHeader *reply)
  {
      RTSPState *rt = s->priv_data;
      char cmd[1024];
      unsigned char *content = NULL;
      int ret;
  
      /* describe the stream */
      snprintf(cmd, sizeof(cmd),
               "Accept: application/sdp\r\n");
      if (rt->server_type == RTSP_SERVER_REAL) {
          /**
           * The Require: attribute is needed for proper streaming from
           * Realmedia servers.
           */
          av_strlcat(cmd,
                     "Require: com.real.retain-entity-for-setup\r\n",
                     sizeof(cmd));
      }
      ff_rtsp_send_cmd(s, "DESCRIBE", rt->control_uri, cmd, reply, &content);
      if (!content)
          return AVERROR_INVALIDDATA;
      if (reply->status_code != RTSP_STATUS_OK) {
          av_freep(&content);
          return AVERROR_INVALIDDATA;
      }
  
      /* now we got the SDP description, we parse it */
      ret = sdp_parse(s, (const char *)content);
      av_freep(&content);
      if (ret < 0)
          return AVERROR_INVALIDDATA;
  
      return 0;
  }
  
  static int rtsp_setup_output_streams(AVFormatContext *s, const char *addr)
  {
      RTSPState *rt = s->priv_data;
      RTSPMessageHeader reply1, *reply = &reply1;
      int i;
      char *sdp;
      AVFormatContext sdp_ctx, *ctx_array[1];
  
      rt->start_time = av_gettime();
  
      /* Announce the stream */
      sdp = av_mallocz(8192);
      if (sdp == NULL)
          return AVERROR(ENOMEM);
      /* We create the SDP based on the RTSP AVFormatContext where we
       * aren't allowed to change the filename field. (We create the SDP
       * based on the RTSP context since the contexts for the RTP streams
       * don't exist yet.) In order to specify a custom URL with the actual
       * peer IP instead of the originally specified hostname, we create
       * a temporary copy of the AVFormatContext, where the custom URL is set.
       *
       * FIXME: Create the SDP without copying the AVFormatContext.
       * This either requires setting up the RTP stream AVFormatContexts
       * already here (complicating things immensely) or getting a more
       * flexible SDP creation interface.
       */
      sdp_ctx = *s;
      ff_url_join(sdp_ctx.filename, sizeof(sdp_ctx.filename),
                  "rtsp", NULL, addr, -1, NULL);
      ctx_array[0] = &sdp_ctx;
      if (avf_sdp_create(ctx_array, 1, sdp, 8192)) {
          av_free(sdp);
          return AVERROR_INVALIDDATA;
      }
      av_log(s, AV_LOG_INFO, "SDP:\n%s\n", sdp);
      ff_rtsp_send_cmd_with_content(s, "ANNOUNCE", rt->control_uri,
                                    "Content-Type: application/sdp\r\n",
                                    reply, NULL, sdp, strlen(sdp));
      av_free(sdp);
      if (reply->status_code != RTSP_STATUS_OK)
          return AVERROR_INVALIDDATA;
  
      /* Set up the RTSPStreams for each AVStream */
      for (i = 0; i < s->nb_streams; i++) {
          RTSPStream *rtsp_st;
          AVStream *st = s->streams[i];
  
          rtsp_st = av_mallocz(sizeof(RTSPStream));
          if (!rtsp_st)
              return AVERROR(ENOMEM);
          dynarray_add(&rt->rtsp_streams, &rt->nb_rtsp_streams, rtsp_st);
  
          st->priv_data = rtsp_st;
          rtsp_st->stream_index = i;
  
          av_strlcpy(rtsp_st->control_url, rt->control_uri, sizeof(rtsp_st->control_url));
          /* Note, this must match the relative uri set in the sdp content */
          av_strlcatf(rtsp_st->control_url, sizeof(rtsp_st->control_url),
                      "/streamid=%d", i);
      }
  
      return 0;
  }
  
  void ff_rtsp_close_connections(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
      if (rt->rtsp_hd_out != rt->rtsp_hd) url_close(rt->rtsp_hd_out);
      url_close(rt->rtsp_hd);
      rt->rtsp_hd = rt->rtsp_hd_out = NULL;
  }
  
  int ff_rtsp_connect(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
      char host[1024], path[1024], tcpname[1024], cmd[2048], auth[128];
      char *option_list, *option, *filename;
      int port, err, tcp_fd;
      RTSPMessageHeader reply1 = {}, *reply = &reply1;
      int lower_transport_mask = 0;
      char real_challenge[64];
      struct sockaddr_storage peer;
      socklen_t peer_len = sizeof(peer);
  
      if (!ff_network_init())
          return AVERROR(EIO);
  redirect:
      rt->control_transport = RTSP_MODE_PLAIN;
      /* extract hostname and port */
      av_url_split(NULL, 0, auth, sizeof(auth),
                   host, sizeof(host), &port, path, sizeof(path), s->filename);
      if (*auth) {
          av_strlcpy(rt->auth, auth, sizeof(rt->auth));
      }
      if (port < 0)
          port = RTSP_DEFAULT_PORT;
  
      /* search for options */
      option_list = strrchr(path, '?');
      if (option_list) {
          /* Strip out the RTSP specific options, write out the rest of
           * the options back into the same string. */
          filename = option_list;
          while (option_list) {
              /* move the option pointer */
              option = ++option_list;
              option_list = strchr(option_list, '&');
              if (option_list)
                  *option_list = 0;
  
              /* handle the options */
              if (!strcmp(option, "udp")) {
                  lower_transport_mask |= (1<< RTSP_LOWER_TRANSPORT_UDP);
              } else if (!strcmp(option, "multicast")) {
                  lower_transport_mask |= (1<< RTSP_LOWER_TRANSPORT_UDP_MULTICAST);
              } else if (!strcmp(option, "tcp")) {
                  lower_transport_mask |= (1<< RTSP_LOWER_TRANSPORT_TCP);
              } else if(!strcmp(option, "http")) {
                  lower_transport_mask |= (1<< RTSP_LOWER_TRANSPORT_TCP);
                  rt->control_transport = RTSP_MODE_TUNNEL;
              } else {
                  /* Write options back into the buffer, using memmove instead
                   * of strcpy since the strings may overlap. */
                  int len = strlen(option);
                  memmove(++filename, option, len);
                  filename += len;
                  if (option_list) *filename = '&';
              }
          }
          *filename = 0;
      }
  
      if (!lower_transport_mask)
          lower_transport_mask = (1 << RTSP_LOWER_TRANSPORT_NB) - 1;
  
      if (s->oformat) {
          /* Only UDP or TCP - UDP multicast isn't supported. */
          lower_transport_mask &= (1 << RTSP_LOWER_TRANSPORT_UDP) |
                                  (1 << RTSP_LOWER_TRANSPORT_TCP);
          if (!lower_transport_mask || rt->control_transport == RTSP_MODE_TUNNEL) {
              av_log(s, AV_LOG_ERROR, "Unsupported lower transport method, "
                                      "only UDP and TCP are supported for output.\n");
              err = AVERROR(EINVAL);
              goto fail;
          }
      }
  
      /* Construct the URI used in request; this is similar to s->filename,
       * but with authentication credentials removed and RTSP specific options
       * stripped out. */
      ff_url_join(rt->control_uri, sizeof(rt->control_uri), "rtsp", NULL,
                  host, port, "%s", path);
  
      if (rt->control_transport == RTSP_MODE_TUNNEL) {
          /* set up initial handshake for tunneling */
          char httpname[1024];
          char sessioncookie[17];
          char headers[1024];
  
          ff_url_join(httpname, sizeof(httpname), "http", auth, host, port, "%s", path);
          snprintf(sessioncookie, sizeof(sessioncookie), "%08x%08x",
                   av_get_random_seed(), av_get_random_seed());
  
          /* GET requests */
          if (url_alloc(&rt->rtsp_hd, httpname, URL_RDONLY) < 0) {
              err = AVERROR(EIO);
              goto fail;
          }
  
          /* generate GET headers */
          snprintf(headers, sizeof(headers),
                   "x-sessioncookie: %s\r\n"
                   "Accept: application/x-rtsp-tunnelled\r\n"
                   "Pragma: no-cache\r\n"
                   "Cache-Control: no-cache\r\n",
                   sessioncookie);
          ff_http_set_headers(rt->rtsp_hd, headers);
  
          /* complete the connection */
          if (url_connect(rt->rtsp_hd)) {
              err = AVERROR(EIO);
              goto fail;
          }
  
          /* POST requests */
          if (url_alloc(&rt->rtsp_hd_out, httpname, URL_WRONLY) < 0 ) {
              err = AVERROR(EIO);
              goto fail;
          }
  
          /* generate POST headers */
          snprintf(headers, sizeof(headers),
                   "x-sessioncookie: %s\r\n"
                   "Content-Type: application/x-rtsp-tunnelled\r\n"
                   "Pragma: no-cache\r\n"
                   "Cache-Control: no-cache\r\n"
                   "Content-Length: 32767\r\n"
                   "Expires: Sun, 9 Jan 1972 00:00:00 GMT\r\n",
                   sessioncookie);
          ff_http_set_headers(rt->rtsp_hd_out, headers);
          ff_http_set_chunked_transfer_encoding(rt->rtsp_hd_out, 0);
  
          /* Initialize the authentication state for the POST session. The HTTP
           * protocol implementation doesn't properly handle multi-pass
           * authentication for POST requests, since it would require one of
           * the following:
           * - implementing Expect: 100-continue, which many HTTP servers
           *   don't support anyway, even less the RTSP servers that do HTTP
           *   tunneling
           * - sending the whole POST data until getting a 401 reply specifying
           *   what authentication method to use, then resending all that data
           * - waiting for potential 401 replies directly after sending the
           *   POST header (waiting for some unspecified time)
           * Therefore, we copy the full auth state, which works for both basic
           * and digest. (For digest, we would have to synchronize the nonce
           * count variable between the two sessions, if we'd do more requests
           * with the original session, though.)
           */
          ff_http_init_auth_state(rt->rtsp_hd_out, rt->rtsp_hd);
  
          /* complete the connection */
          if (url_connect(rt->rtsp_hd_out)) {
              err = AVERROR(EIO);
              goto fail;
          }
      } else {
          /* open the tcp connection */
          ff_url_join(tcpname, sizeof(tcpname), "tcp", NULL, host, port, NULL);
          if (url_open(&rt->rtsp_hd, tcpname, URL_RDWR) < 0) {
              err = AVERROR(EIO);
              goto fail;
          }
          rt->rtsp_hd_out = rt->rtsp_hd;
      }
      rt->seq = 0;
  
      tcp_fd = url_get_file_handle(rt->rtsp_hd);
      if (!getpeername(tcp_fd, (struct sockaddr*) &peer, &peer_len)) {
          getnameinfo((struct sockaddr*) &peer, peer_len, host, sizeof(host),
                      NULL, 0, NI_NUMERICHOST);
      }
  
      /* request options supported by the server; this also detects server
       * type */
      for (rt->server_type = RTSP_SERVER_RTP;;) {
          cmd[0] = 0;
          if (rt->server_type == RTSP_SERVER_REAL)
              av_strlcat(cmd,
                         /**
                          * The following entries are required for proper
                          * streaming from a Realmedia server. They are
                          * interdependent in some way although we currently
                          * don't quite understand how. Values were copied
                          * from mplayer SVN r23589.
                          * @param CompanyID is a 16-byte ID in base64
                          * @param ClientChallenge is a 16-byte ID in hex
                          */
                         "ClientChallenge: 9e26d33f2984236010ef6253fb1887f7\r\n"
                         "PlayerStarttime: [28/03/2003:22:50:23 00:00]\r\n"
                         "CompanyID: KnKV4M4I/B2FjJ1TToLycw==\r\n"
                         "GUID: 00000000-0000-0000-0000-000000000000\r\n",
                         sizeof(cmd));
          ff_rtsp_send_cmd(s, "OPTIONS", rt->control_uri, cmd, reply, NULL);
          if (reply->status_code != RTSP_STATUS_OK) {
              err = AVERROR_INVALIDDATA;
              goto fail;
          }
  
          /* detect server type if not standard-compliant RTP */
          if (rt->server_type != RTSP_SERVER_REAL && reply->real_challenge[0]) {
              rt->server_type = RTSP_SERVER_REAL;
              continue;
          } else if (!strncasecmp(reply->server, "WMServer/", 9)) {
              rt->server_type = RTSP_SERVER_WMS;
          } else if (rt->server_type == RTSP_SERVER_REAL)
              strcpy(real_challenge, reply->real_challenge);
          break;
      }
  
      if (s->iformat)
          err = rtsp_setup_input_streams(s, reply);
      else
          err = rtsp_setup_output_streams(s, host);
      if (err)
          goto fail;
  
      do {
          int lower_transport = ff_log2_tab[lower_transport_mask &
                                    ~(lower_transport_mask - 1)];
  
          err = make_setup_request(s, host, port, lower_transport,
                                   rt->server_type == RTSP_SERVER_REAL ?
                                       real_challenge : NULL);
          if (err < 0)
              goto fail;
          lower_transport_mask &= ~(1 << lower_transport);
          if (lower_transport_mask == 0 && err == 1) {
              err = FF_NETERROR(EPROTONOSUPPORT);
              goto fail;
          }
      } while (err);
  
      rt->state = RTSP_STATE_IDLE;
      rt->seek_timestamp = 0; /* default is to start stream at position zero */
      return 0;
   fail:
      ff_rtsp_close_streams(s);
      ff_rtsp_close_connections(s);
      if (reply->status_code >=300 && reply->status_code < 400 && s->iformat) {
          av_strlcpy(s->filename, reply->location, sizeof(s->filename));
          av_log(s, AV_LOG_INFO, "Status %d: Redirecting to %s\n",
                 reply->status_code,
                 s->filename);
          goto redirect;
      }
      ff_network_close();
      return err;
  }
  #endif
  
  #if CONFIG_RTSP_DEMUXER
  static int rtsp_read_header(AVFormatContext *s,
                              AVFormatParameters *ap)
  {
      int ret;
  
      ret = ff_rtsp_connect(s);
      if (ret)
          return ret;
  
      if (ap->initial_pause) {
           /* do not start immediately */
      } else {
           if (rtsp_read_play(s) < 0) {
              ff_rtsp_close_streams(s);
              ff_rtsp_close_connections(s);
              return AVERROR_INVALIDDATA;
          }
      }
  
      return 0;
  }
  
  static int udp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
                             uint8_t *buf, int buf_size)
  {
      RTSPState *rt = s->priv_data;
      RTSPStream *rtsp_st;
      fd_set rfds;
      int fd, fd_max, n, i, ret, tcp_fd, timeout_cnt = 0;
      struct timeval tv;
  
      for (;;) {
          if (url_interrupt_cb())
              return AVERROR(EINTR);
          FD_ZERO(&rfds);
          if (rt->rtsp_hd) {
              tcp_fd = fd_max = url_get_file_handle(rt->rtsp_hd);
              FD_SET(tcp_fd, &rfds);
          } else {
              fd_max = 0;
              tcp_fd = -1;
          }
          for (i = 0; i < rt->nb_rtsp_streams; i++) {
              rtsp_st = rt->rtsp_streams[i];
              if (rtsp_st->rtp_handle) {
                  /* currently, we cannot probe RTCP handle because of
                   * blocking restrictions */
                  fd = url_get_file_handle(rtsp_st->rtp_handle);
                  if (fd > fd_max)
                      fd_max = fd;
                  FD_SET(fd, &rfds);
              }
          }
          tv.tv_sec = 0;
          tv.tv_usec = SELECT_TIMEOUT_MS * 1000;
          n = select(fd_max + 1, &rfds, NULL, NULL, &tv);
          if (n > 0) {
              timeout_cnt = 0;
              for (i = 0; i < rt->nb_rtsp_streams; i++) {
                  rtsp_st = rt->rtsp_streams[i];
                  if (rtsp_st->rtp_handle) {
                      fd = url_get_file_handle(rtsp_st->rtp_handle);
                      if (FD_ISSET(fd, &rfds)) {
                          ret = url_read(rtsp_st->rtp_handle, buf, buf_size);
                          if (ret > 0) {
                              *prtsp_st = rtsp_st;
                              return ret;
                          }
                      }
                  }
              }
  #if CONFIG_RTSP_DEMUXER
              if (tcp_fd != -1 && FD_ISSET(tcp_fd, &rfds)) {
                  RTSPMessageHeader reply;
  
                  ret = ff_rtsp_read_reply(s, &reply, NULL, 0);
                  if (ret < 0)
                      return ret;
                  /* XXX: parse message */
                  if (rt->state != RTSP_STATE_STREAMING)
                      return 0;
              }
  #endif
          } else if (n == 0 && ++timeout_cnt >= MAX_TIMEOUTS) {
              return FF_NETERROR(ETIMEDOUT);
          } else if (n < 0 && errno != EINTR)
              return AVERROR(errno);
      }
  }
  
  static int tcp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
                             uint8_t *buf, int buf_size)
  {
      RTSPState *rt = s->priv_data;
      int id, len, i, ret;
      RTSPStream *rtsp_st;
  
  #ifdef DEBUG_RTP_TCP
      dprintf(s, "tcp_read_packet:\n");
  #endif
  redo:
      for (;;) {
          RTSPMessageHeader reply;
  
          ret = ff_rtsp_read_reply(s, &reply, NULL, 1);
          if (ret == -1)
              return -1;
          if (ret == 1) /* received '$' */
              break;
          /* XXX: parse message */
          if (rt->state != RTSP_STATE_STREAMING)
              return 0;
      }
      ret = url_read_complete(rt->rtsp_hd, buf, 3);
      if (ret != 3)
          return -1;
      id  = buf[0];
      len = AV_RB16(buf + 1);
  #ifdef DEBUG_RTP_TCP
      dprintf(s, "id=%d len=%d\n", id, len);
  #endif
      if (len > buf_size || len < 12)
          goto redo;
      /* get the data */
      ret = url_read_complete(rt->rtsp_hd, buf, len);
      if (ret != len)
          return -1;
      if (rt->transport == RTSP_TRANSPORT_RDT &&
          ff_rdt_parse_header(buf, len, &id, NULL, NULL, NULL, NULL) < 0)
          return -1;
  
      /* find the matching stream */
      for (i = 0; i < rt->nb_rtsp_streams; i++) {
          rtsp_st = rt->rtsp_streams[i];
          if (id >= rtsp_st->interleaved_min &&
              id <= rtsp_st->interleaved_max)
              goto found;
      }
      goto redo;
  found:
      *prtsp_st = rtsp_st;
      return len;
  }
  
  static int rtsp_fetch_packet(AVFormatContext *s, AVPacket *pkt)
  {
      RTSPState *rt = s->priv_data;
      int ret, len;
      uint8_t buf[10 * RTP_MAX_PACKET_LENGTH];
      RTSPStream *rtsp_st;
  
      /* get next frames from the same RTP packet */
      if (rt->cur_transport_priv) {
          if (rt->transport == RTSP_TRANSPORT_RDT) {
              ret = ff_rdt_parse_packet(rt->cur_transport_priv, pkt, NULL, 0);
          } else
              ret = rtp_parse_packet(rt->cur_transport_priv, pkt, NULL, 0);
          if (ret == 0) {
              rt->cur_transport_priv = NULL;
              return 0;
          } else if (ret == 1) {
              return 0;
          } else
              rt->cur_transport_priv = NULL;
      }
  
      /* read next RTP packet */
   redo:
      switch(rt->lower_transport) {
      default:
  #if CONFIG_RTSP_DEMUXER
      case RTSP_LOWER_TRANSPORT_TCP:
          len = tcp_read_packet(s, &rtsp_st, buf, sizeof(buf));
          break;
  #endif
      case RTSP_LOWER_TRANSPORT_UDP:
      case RTSP_LOWER_TRANSPORT_UDP_MULTICAST:
          len = udp_read_packet(s, &rtsp_st, buf, sizeof(buf));
          if (len >=0 && rtsp_st->transport_priv && rt->transport == RTSP_TRANSPORT_RTP)
              rtp_check_and_send_back_rr(rtsp_st->transport_priv, len);
          break;
      }
      if (len < 0)
          return len;
      if (len == 0)
          return AVERROR_EOF;
      if (rt->transport == RTSP_TRANSPORT_RDT) {
          ret = ff_rdt_parse_packet(rtsp_st->transport_priv, pkt, buf, len);
      } else {
          ret = rtp_parse_packet(rtsp_st->transport_priv, pkt, buf, len);
          if (ret < 0) {
              /* Either bad packet, or a RTCP packet. Check if the
               * first_rtcp_ntp_time field was initialized. */
              RTPDemuxContext *rtpctx = rtsp_st->transport_priv;
              if (rtpctx->first_rtcp_ntp_time != AV_NOPTS_VALUE) {
                  /* first_rtcp_ntp_time has been initialized for this stream,
                   * copy the same value to all other uninitialized streams,
                   * in order to map their timestamp origin to the same ntp time
                   * as this one. */
                  int i;
                  for (i = 0; i < rt->nb_rtsp_streams; i++) {
                      RTPDemuxContext *rtpctx2 = rtsp_st->transport_priv;
                      if (rtpctx2 &&
                          rtpctx2->first_rtcp_ntp_time == AV_NOPTS_VALUE)
                          rtpctx2->first_rtcp_ntp_time = rtpctx->first_rtcp_ntp_time;
                  }
              }
          }
      }
      if (ret < 0)
          goto redo;
      if (ret == 1)
          /* more packets may follow, so we save the RTP context */
          rt->cur_transport_priv = rtsp_st->transport_priv;
  
      return ret;
  }
  
  static int rtsp_read_packet(AVFormatContext *s, AVPacket *pkt)
  {
      RTSPState *rt = s->priv_data;
      int ret;
      RTSPMessageHeader reply1, *reply = &reply1;
      char cmd[1024];
  
      if (rt->server_type == RTSP_SERVER_REAL) {
          int i;
          enum AVDiscard cache[MAX_STREAMS];
  
          for (i = 0; i < s->nb_streams; i++)
              cache[i] = s->streams[i]->discard;
  
          if (!rt->need_subscription) {
              if (memcmp (cache, rt->real_setup_cache,
                          sizeof(enum AVDiscard) * s->nb_streams)) {
                  snprintf(cmd, sizeof(cmd),
                           "Unsubscribe: %s\r\n",
                           rt->last_subscription);
                  ff_rtsp_send_cmd(s, "SET_PARAMETER", rt->control_uri,
                                   cmd, reply, NULL);
                  if (reply->status_code != RTSP_STATUS_OK)
                      return AVERROR_INVALIDDATA;
                  rt->need_subscription = 1;
              }
          }
  
          if (rt->need_subscription) {
              int r, rule_nr, first = 1;
  
              memcpy(rt->real_setup_cache, cache,
                     sizeof(enum AVDiscard) * s->nb_streams);
              rt->last_subscription[0] = 0;
  
              snprintf(cmd, sizeof(cmd),
                       "Subscribe: ");
              for (i = 0; i < rt->nb_rtsp_streams; i++) {
                  rule_nr = 0;
                  for (r = 0; r < s->nb_streams; r++) {
                      if (s->streams[r]->priv_data == rt->rtsp_streams[i]) {
                          if (s->streams[r]->discard != AVDISCARD_ALL) {
                              if (!first)
                                  av_strlcat(rt->last_subscription, ",",
                                             sizeof(rt->last_subscription));
                              ff_rdt_subscribe_rule(
                                  rt->last_subscription,
                                  sizeof(rt->last_subscription), i, rule_nr);
                              first = 0;
                          }
                          rule_nr++;
                      }
                  }
              }
              av_strlcatf(cmd, sizeof(cmd), "%s\r\n", rt->last_subscription);
              ff_rtsp_send_cmd(s, "SET_PARAMETER", rt->control_uri,
                               cmd, reply, NULL);
              if (reply->status_code != RTSP_STATUS_OK)
                  return AVERROR_INVALIDDATA;
              rt->need_subscription = 0;
  
              if (rt->state == RTSP_STATE_STREAMING)
                  rtsp_read_play (s);
          }
      }
  
      ret = rtsp_fetch_packet(s, pkt);
      if (ret < 0)
          return ret;
  
      /* send dummy request to keep TCP connection alive */
      if ((rt->server_type == RTSP_SERVER_WMS ||
           rt->server_type == RTSP_SERVER_REAL) &&
          (av_gettime() - rt->last_cmd_time) / 1000000 >= rt->timeout / 2) {
          if (rt->server_type == RTSP_SERVER_WMS) {
              ff_rtsp_send_cmd_async(s, "GET_PARAMETER", rt->control_uri, NULL);
          } else {
              ff_rtsp_send_cmd_async(s, "OPTIONS", "*", NULL);
          }
      }
  
      return 0;
  }
  
  /* pause the stream */
  static int rtsp_read_pause(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
      RTSPMessageHeader reply1, *reply = &reply1;
  
      if (rt->state != RTSP_STATE_STREAMING)
          return 0;
      else if (!(rt->server_type == RTSP_SERVER_REAL && rt->need_subscription)) {
          ff_rtsp_send_cmd(s, "PAUSE", rt->control_uri, NULL, reply, NULL);
          if (reply->status_code != RTSP_STATUS_OK) {
              return -1;
          }
      }
      rt->state = RTSP_STATE_PAUSED;
      return 0;
  }
  
  static int rtsp_read_seek(AVFormatContext *s, int stream_index,
                            int64_t timestamp, int flags)
  {
      RTSPState *rt = s->priv_data;
  
      rt->seek_timestamp = av_rescale_q(timestamp,
                                        s->streams[stream_index]->time_base,
                                        AV_TIME_BASE_Q);
      switch(rt->state) {
      default:
      case RTSP_STATE_IDLE:
          break;
      case RTSP_STATE_STREAMING:
          if (rtsp_read_pause(s) != 0)
              return -1;
          rt->state = RTSP_STATE_SEEKING;
          if (rtsp_read_play(s) != 0)
              return -1;
          break;
      case RTSP_STATE_PAUSED:
          rt->state = RTSP_STATE_IDLE;
          break;
      }
      return 0;
  }
  
  static int rtsp_read_close(AVFormatContext *s)
  {
      RTSPState *rt = s->priv_data;
  
  #if 0
      /* NOTE: it is valid to flush the buffer here */
      if (rt->lower_transport == RTSP_LOWER_TRANSPORT_TCP) {
          url_fclose(&rt->rtsp_gb);
      }
  #endif
      ff_rtsp_send_cmd_async(s, "TEARDOWN", rt->control_uri, NULL);
  
      ff_rtsp_close_streams(s);
      ff_rtsp_close_connections(s);
      ff_network_close();
      return 0;
  }
  
  AVInputFormat rtsp_demuxer = {
      "rtsp",
      NULL_IF_CONFIG_SMALL("RTSP input format"),
      sizeof(RTSPState),
      rtsp_probe,
      rtsp_read_header,
      rtsp_read_packet,
      rtsp_read_close,
      rtsp_read_seek,
      .flags = AVFMT_NOFILE,
      .read_play = rtsp_read_play,
      .read_pause = rtsp_read_pause,
  };
  #endif
  
  static int sdp_probe(AVProbeData *p1)
  {
      const char *p = p1->buf, *p_end = p1->buf + p1->buf_size;
  
      /* we look for a line beginning "c=IN IP4" */
      while (p < p_end && *p != '\0') {
          if (p + sizeof("c=IN IP4") - 1 < p_end &&
              av_strstart(p, "c=IN IP4", NULL))
              return AVPROBE_SCORE_MAX / 2;
  
          while (p < p_end - 1 && *p != '\n') p++;
          if (++p >= p_end)
              break;
          if (*p == '\r')
              p++;
      }
      return 0;
  }
  
  #define SDP_MAX_SIZE 8192
  
  static int sdp_read_header(AVFormatContext *s, AVFormatParameters *ap)
  {
      RTSPState *rt = s->priv_data;
      RTSPStream *rtsp_st;
      int size, i, err;
      char *content;
      char url[1024];
  
      if (!ff_network_init())
          return AVERROR(EIO);
  
      /* read the whole sdp file */
      /* XXX: better loading */
      content = av_malloc(SDP_MAX_SIZE);
      size = get_buffer(s->pb, content, SDP_MAX_SIZE - 1);
      if (size <= 0) {
          av_free(content);
          return AVERROR_INVALIDDATA;
      }
      content[size] ='\0';
  
      sdp_parse(s, content);
      av_free(content);
  
      /* open each RTP stream */
      for (i = 0; i < rt->nb_rtsp_streams; i++) {
          rtsp_st = rt->rtsp_streams[i];
  
          ff_url_join(url, sizeof(url), "rtp", NULL,
                      inet_ntoa(rtsp_st->sdp_ip), rtsp_st->sdp_port,
                      "?localport=%d&ttl=%d", rtsp_st->sdp_port,
                      rtsp_st->sdp_ttl);
          if (url_open(&rtsp_st->rtp_handle, url, URL_RDWR) < 0) {
              err = AVERROR_INVALIDDATA;
              goto fail;
          }
          if ((err = rtsp_open_transport_ctx(s, rtsp_st)))
              goto fail;
      }
      return 0;
  fail:
      ff_rtsp_close_streams(s);
      ff_network_close();
      return err;
  }
  
  static int sdp_read_close(AVFormatContext *s)
  {
      ff_rtsp_close_streams(s);
      ff_network_close();
      return 0;
  }
  
  AVInputFormat sdp_demuxer = {
      "sdp",
      NULL_IF_CONFIG_SMALL("SDP"),
      sizeof(RTSPState),
      sdp_probe,
      sdp_read_header,
      rtsp_fetch_packet,
      sdp_read_close,
  };
  